Display device including first and second substrates, one including a pad electrode

ABSTRACT

According to one embodiment, a display device includes a first substrate including as insulating substrate with a first through hole, a pad electrode positioned above the insulating substrate, and a signal line electrically connected to the pad electrode, a second substrate opposed to the first substrate, a sealant which adheres the first substrate and the second substrate, a line substrate including a connection line and disposed below the insulating substrate, and a conductive material which electrically connects the pad electrode and the connection line, wherein the sealant is less absorptive than is the insulating substrate as to a wavelength less than 350 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-042462, filed Mar. 4, 2016, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

In recent years, display devices with a greater display area are highlyanticipated because of higher performance and advanced design in thetechnical field of mobile data communication devices such as mobilephone and personal digital assistant (PDA). For example, display devicesincluding a thinner bezel structure are proposed.

Conventionally, there is a well-known structure in which a driver ismounted in the periphery of the display area on the substrate includingelectrodes. In display devices using such a structure of the driver,input signals and voltages are supplied to the driver through a linesubstrate such as a flexible printed circuit (FPC). On the other hand,instead of such a flexible printed circuit, there has been proposed amethod to form an electrical connection between lines formed on thelower surface side of an array substrate and the driver formed on theupper surface side of the array substrate through a laser-formed contacthole passing through the array substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of the structure of a displaydevice of an embodiment.

FIG. 2 is a cross-sectional view showing a display area of the displaydevice of FIG. 1.

FIG. 3 is a cross-sectional view of the display device of FIG. 1including a non-display area.

FIG. 4 is a cross-sectional view showing a part of the display device ofFIG. 3 in an enlarged manner, in which a line substrate, anisotropyconductive film, first insulating substrate, insulating film, padelectrode, and the like are depicted.

FIG. 5 is a plan view of a first substrate of the embodiment, in whichpositions of a first area and a second area or the like are depicted.

FIG. 6 is a plan view showing a process in which a support substrate ispeeled off from the first insulating substrate.

FIG. 7 is a cross-sectional view showing a process in which a firstprotection member and a second protection member are adhered to thefirst insulating substrate.

FIG. 8 is a cross-sectional view showing a process in which a firstcontact hole is formed in the first insulating substrate.

FIG. 9 is a cross-sectional view showing a process in which the firstinsulating substrate is thinned in the second area and a second contacthole is formed in an insulating film.

FIG. 10 is a cross-sectional view showing a process in which the linesubstrate is pressed to the display panel.

FIG. 11 is a cross-sectional view showing another process of forming afirst contact hole in the first-insulating substrate of FIG. 8.

FIG. 12 is a schematic plan view showing positional relationshipsbetween the pad electrode and the first contact hole.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device includes: afirst substrate including an insulating substrate with a first throughhole, a pad electrode positioned above the insulating substrate, and asignal line electrically connected to the pad electrode; a secondsubstrate opposed to the first substrate; a sealant which adheres thefirst substrate and the second substrate; a line substrate including aconnection line and disposed below the insulating substrate; and aconductive material which electrically connects the pad electrode andthe connection line, wherein the sealant is less absorptive than is theinsulating substrate as to a wavelength less than 350 nm.

According to one embodiment, a display device include: a first substrateincluding an insulating substrate with a first through hole, a padelectrode positioned above the insulating substrate, and a signal lineelectrically connected to the pad electrode; a second substrate opposedto the first substrate; an organic member positioned between the firstsubstrate and the second substrate; a line substrate including aconnection line and disposed below the insulating substrate; and aconductive material which electrically connects the pad electrode andthe connection line, wherein the organic member is less absorptive thanis the insulating substrate as to a wavelength less than 350 nm.

Embodiments will be described hereinafter with reference to theaccompanying drawings. Incidentally, the disclosure is merely anexample, and proper changes within the spirit of the invention, whichare easily conceivable by a skilled person, are included in the scope ofthe invention as a matter of course. In addition, in some cases, inorder to snake the description clearer, the widths, thicknesses, shapes,etc. of the respective parts are schematically illustrated in thedrawings, compared to the actual modes. However, the schematicillustration is merely an example, and adds no restrictions to theinterpretation of the invention. Besides, in the specification anddrawings, the structural elements having functions, which are identicalor similar to the functions of the structural elements described inconnection with preceding drawings, are denoted by like referencenumerals, and an overlapping detailed description is omitted unlessnecessary.

Initially, a display device of a present embodiment will be explained.FIG. 1 is a schematic perspective view showing the structure of adisplay device DSP of the present embodiment. FIG. 1 shows athree-dimensional space which is defined by a first direction X, seconddirection Y which is orthogonal to the first direction X, and thirddirection Z which is orthogonal to the first direction X and the seconddirection Y. Note that, in this example, the first direction X and thesecond direction Y are orthogonal to each other; however, they may crossat an angle other than 90°. Furthermore, in the present embodiment, thedisplay device is an organic electroluminescent (EL) display device.

As shown in FIG. 1, the display device DSP includes a display panel PNLand a line substrate 1. The display panel PNL includes a plate-likefirst substrate SUB1 and a plate-like second substrate SUB2 opposed tothe first substrate SUB1.

In the present embodiment, the positive direction of a third directionZ, or the direction from the first substrate SUB1 to the secondsubstrate SUB2 will be defined as up or above. The negative direction ofthe third direction Z, or the direction from the second substrate SUB2to the first substrate SUB1 will be defined as down or below.Furthermore, phrases such as “a second member above a first member” and“a second member below a first member” may refer to either a case wherethe second member contacts the first member or a case where the secondmember is apart from the first member. In the latter case, a thirdmember may be interposed between the first and second members. On theother hand, phrases such as “a second member on a first member” and “asecond member on the bottom of a first member” refer to a case where thesecond member contacts the first member.

The display panel PNL includes a display area DA in which an image isdisplayed and a non-display area NDA which surrounds the display areaDA. The display panel PNL includes a plurality of pixels PX within thedisplay area DA. The pixels PX are arranged in a matrix in the firstdirection X and the second direction Y.

In the example depicted, a side edge of the first substrate SUB1 whichis parallel to the first direction X and a side edge of the secondsubstrate SUB2 which is parallel to the first direction X have asubstantially same length. Furthermore, a side edge of the firstsubstrate SUB1 which is parallel to the second direction Y and a sideedge of the second substrate SUB2 which is parallel to the seconddirection Y have a substantially same length. That is, an area of thefirst substrate SUB1 which is parallel to the X-Y plane is substantiallythe same as an area of the second substrate SUB2 in the X-Y plane. Inthe present embodiment, each side edge of the first substrate SUB1matches each corresponding edge of the second substrate SUB2 in thethird direction Z.

The line substrate 1 is disposed below the display panel PNL. In thisexample, a side edge of the line substrate 1 which is parallel to thefirst direction X has a length shorter than or equal to the side edgesof the first substrate SUB1 and the second substrate SUB2 which areparallel to the first direction X.

Furthermore, a side edge of the line substrate 1 which is parallel tothe second direction Y has a length shorter than or equal to the sideedges the first substrate SUB1 and the second substrate SUB2 which areparallel to the second direction Y. The line substrate 1 is disposed inboth the non-display area NDA and the display area DA. Mote that theline substrate 1 does not go outside the area opposed to the displaypanel PNL. The display panel PNL and the line substrate 1 areelectrically connected to each other.

FIG. 2 is a cross-sectional view of a display area DA of the displaydevice DSP of FIG. 1.

As shown in FIG. 2, the first substrate SUB1 includes, for example, afirst insulating substrate 10, switching elements SW1, SW2, and SW3,reflective layer 4, organic EL elements OLED1, OLED2, and OLED3, andprotection member PP. The first insulating substrate 10 is formed of anorganic insulating material which is, for example, polyimide. The firstinsulating substrate 10 is covered with a first insulating film 11.

Switching elements SW1, SW2, and SW3 are formed above the firstinsulating film 11. In the example depicted, switching elements SW1,SW2, and SW3 are of top-gate type; however, they may be of bottom-gatetype. Switching elements SW1, SW2, and SW3 are structured the same, andthus, the detailed structure of switching element SW1 will be explainedas a typical example. The switching elements SW1 includes asemiconductor layer SC formed on the first insulating film 11. Thesemiconductor layer SC is covered with a second insulating film 12.Furthermore, the second insulating film 12 is disposed on the firstinsulating film 11.

A gate electrode WG of the switching element SW1 is formed on the secondinsulating film 12 and is positioned directly above the semiconductorlayer SC. The gate electrode WG is covered with a third insulating film13. The third insulating film 13 is disposed on the second insulatingfilm 12.

The first, insulating film 11, second insulating film 12, and thirdinsulating film 13 are formed of an inorganic material such as a siliconoxide or a silicon nitride.

A source electrode WS and a drain electrode WD of the switching elementSW1 are formed on the third insulating film 13. The source electrode WSand the drain electrode WD are electrically connected to thesemiconductor layer SC through a contact hole passing through the secondinsulating film 12 and the third insulating film 13. The switchingelement SW1 is covered with a fourth insulating film 14. The fourthinsulating film 14 is disposed on the third insulating film 13. Thefourth insulating film 14 is formed of an organic material such astransparent resin.

The reflective layer 4 is formed on the fourth insulating film 14. Thereflective layer 4 is formed of a highly reflective metal material suchas aluminum and silver. Note that the reflective layer 4 (that is, thesurface in the second substrate SUB2 side) may have either a flatsurface or an asperity for light dispersion.

Organic EL elements (light emitting elements) OLED1 to OLED3 aredisposed between the first substrate SUB1 and the second substrate SUB2.Furthermore, the organic EL elements OLED1 to OLED3 are formed on thefourth insulating film 14. In the example depicted, the organic ELelement OLED1 is electrically connected to the switching element SW1,the organic EL element OLED2 is electrically connected to the switchingelement SW2, and the organic EL element OLED3 is electrically connectedto the switching element SW3. Each of the organic EL elements OLED1 toOLED3 is structured as a top-emission type which emits whit light towardthe second substrate SUB2. The organic EL elements OLED1 to OLED3 havethe same structure.

The organic EL elements OLED1 includes a positive electrode PE1 formedon the reflective layer 4. The positive electrode PE1 contacts the drainelectrode WD of the switching element SW1 and is electrically connectedto the switching element SW1. Similarly, the organic EL element OLED2includes a positive electrode PE2 which is electrically connected to theswitching element SW2 and the organic EL element OLED3 includes apositive electrode PE3 which is electrically connected to the switchingelement SW3. The positive electrodes PE1, PE2, and PE3 are formed of atransparent conductive material such as indium tin oxide (ITO) or indiumzinc oxide (ISO).

The organic EL elements OLED1 to OLED3 each include an organic lightemitting layer ORG and a common electrode (negative electrode) CE. Theorganic light emitting layer ORG is disposed on each of the positiveelectrodes PE1 to PE3. The common electrode CE is positioned above theorganic light emitting layer ORG. The common electrode CE is formed of atransparent conductive material such as ITO or IZO. In the exampledepicted, the organic EL elements OLED1 to OLED3 are defined by ribs 15.Note that, although this is not depicted, each of the organic ELelements OLED1 to OLED3 is, preferably, sealed by a transparentshielding film.

The second substrate SUB2 is disposed above the first substrate SUB1.The second substrate SUB2 includes a second insulating substrate 30, acolor filter layer 220 and the like. The second insulating substrate 30may be a glass substrate or a resin substrate, or may be an opticaldevice including an optical film, a polarizer, or the like.

The color filter layer 220 is disposed in the inner surface 30A side ofthe second insulating substrate 30. The color filter layer 220 includescolor filters CF1, CF2, and CF3. The color filters CF1, CF2, and CF3 areformed of resin materials of different colors. In this example, thecolor filter CF1 is a blue color filter. The color filter CF2 is a greencolor filter. The color filter CF3 is a red color filter. Note that thecolor filter layer 220 may further include a white or a transparentcolor filter. The color filters CF1, CF2, and CF3 are opposed to theorganic EL elements OLED1, OLED2, and OLED3, respectively.

The first substrate SUB1 and the second substrate SUB2 are adheredtogether by a transparent acrylate 41 in the display area DA. As will bedescribed later, the first substrate SUB1 and the second substrate SUB2may be adhered by the acrylate 41 in the non-display area NDA or by asealant surrounding the display area DA in the non-display area NDA.

A protection member PP is disposed below the first insulating substrate10. In the example, the protection member PP is adhered to the bottom ofthe first insulating substrate 10; however, an additional thin film maybe interposed between the protection member PP and the first insulatingsubstrate 10. The protection member PP is, preferably, formed of amaterial which exerts a good heat resistivity, gas insulation,anti-humidity, and strength, and also is cheap. The protection member PPis such heat resistive that it does not change or deform in a processtemperature during a manufacturing process of the display device DSP.Furthermore, the protection member PP has a strength greater than thatof the first insulating substrate 10 and functions as a supportive layerwhich suppresses bending of the display panel PNL. Furthermore, theprotection member PP has an anti-humidity property to keep water or thelike from entering the inside and a gas insulation property to keep gasor the like from entering the inside, and functions as a barrier layer.In the present embodiment, the protection member PP is a film formed of,for example, polyethylene terephthalate.

Note that, a metal layer may be formed below the protection member PP.The metal layer is, for example, a thin film deposited on the protectionmember PP, and another thin film may be interposed between theprotection member PP and the metal layer. The metal layer is,preferably, formed of a material which exerts gas insulation greaterthan that of the protection member PP in consideration of themanufacturing process which will be described later, and such a materialwill be, for example, aluminum or an aluminum alloy.

In the above display device, when the organic EL elements OLED1 to OLED3emit light, the light (white light) irradiated from the elements OLED1to OLED3 exits through the color filters CF1, CF2, and CF3. Therein, thelight of blue wave length in the white light irradiated from the organicEL element OLED1 passes the color filter CF1. Additionally, the light ofgreen wave length in the white light irradiated from the organic ELelement OLED2 passes the color filter CE2, and the light of red wavelength in the white light irradiated from the organic EL element OLED3passes the color filter CF3. Therefore, color image display can beachieved.

A pixel PX shown in FIG. 1 is, for example, a minimum unit of a colorimage, and includes the above-described organic EL elements OLED1 toOLED3.

Note that, in the above example, the organic EL elements OLED1 to OLED3include a common organic light emitting layer ORG; however, nolimitation is intended thereby. For example, the organic EL elementsOLED1 may include an organic light emitting layer which emits bluelight, the organic EL element OLED2 may include an organic lightemitting layer which emits green light, and the organic EL elementsOLED3 may include an organic light emitting layer which emits red light,and in such a structural example, the color filter layer 220 may beomitted.

FIG. 3 is a cross-sectional view of the display device DSP of FIG. 1including the non-display area NDA. Note that, in this example, thestructure of the second substrate SUB2 is substantially the same as inFIG. 2, and thus, the detailed structure thereof will not be mentioned.Furthermore, in the present embodiment, viewing the first substrate SUB1from the second substrate SUB2 will be defined as a plan view.

As shown in FIG. 3, the first substrate SUB1 and the second substrateSUB2 are adhered by an acrylate 41 and a sealant SL. The sealant SL isformed in the non-display area NDA. The acrylate 41 is disposed in anarea surrounded by the first substrate SUB1, second substrate SUB2, andsealant SL. In the present embodiment, the acrylate 41 is formed of anepoxy, acryl, or epoxy acrylate resin material. Furthermore, the sealantSL is formed of an ultraviolet laser resistive material as will bedescribed later, and is formed of, for example, a resin material havingan acrylate skeleton.

In this example, the sealant SL is formed of an ultraviolet cured andthermal cured resin material. A formation process of the sealant SL willbe explained briefly. Initially, a composition for a sealant isprepared. The composition is a precursor of the sealant SL, and is aliquid of high viscosity including optical cured resin monomer,polymerization initiator, cross-link agent, and various additives. Sucha composition is applied to the first substrate SUB1 or the secondsubstrate SUB2. The composition may be applied by drawing suing adispenser, or by printing using a printing plate, or by drawing using anink-jet device. Then, the first substrate SUB1 and the second substrateSUB2 are adhered and aligned, and the polymerization reaction of thecomposition is started through ultraviolet irradiation and heatapplication to the composition for the cure thereof. Note that, in theultraviolet irradiation, the display area DA is, preferably, coveredwith a mask for ultraviolet-protection. Then, the composition issintered to be fully cured.

Note that the acrylate 41 and the sealant SL may be formed of the samematerial or different materials. If the acrylate 41 and the sealant SLare formed of the same material, the acrylate 41 and the sealant SL isformed of an acryl or epoxy acrylate resin material. Or, the sealant SLmay be omitted and the acrylate 41 may extend in the position of thesealant SL.

The first insulating substrate 10 includes a first area AR1 and a secondarea AR2 which are adjacent to each other. The first area AR1corresponds to an area of the first insulating substrate 10 overlappingthe protection member PP in the third direction Z, and the second areaAR2 corresponds to an area of the first insulating substrate 10 notoverlapping the first protection member PP in the third direction Z. Thefirst protection member PP is disposed below the first area AR1 of thefirst insulating substrate 10 and is not disposed below the second areaAR2.

The second area AR2 is formed thinner than the first area AR1. The firstinsulating substrate 10 has a thickness W1 in the first area AR1 and athickness W2 in the second area AR2. The thickness W2 is less than thethickness W1. In the present embodiment, the thickness W1 isapproximately 10 μm, and the thickness W2 is 1 μm or less, for example.

A pad electrode PD is formed above the first insulating substrate 10.Note that a second contact hole CHa2 is formed between the pad electrodePD and a first contact hole CHa1. As shown in FIG. 2, the firstinsulating film 11, second insulating film 12, and third insulating film13 are disposed between the pad electrode PD and the first insulatingsubstrate 10. Here, the first to third insulating films 11 to 13disposed between the first insulating substrate 10 and the pad electrodePD are referred to as an insulating film IL. That is, the insulatingfilm IL is an inorganic insulating film. Here, for example, the firstinsulating film 11 and the second insulating film 12 are formed ofdifferent materials. In the example depicted, the pad electrode PD is amultilayer of the first electrode P1 and the second electrode P2. Thefirst electrode P1 is a transparent conductive layer formed of atransparent conductive material such as indium tin oxide (ITO).Furthermore, the first electrode P1 contacts an anisotropy conductivefilm 3. The second electrode P2 is disposed on the first electrode P1.The second electrode P2 is formed of a metal material such as aluminum.The first electrode P1 is formed in, for example, an island shape.

The fourth insulating film 14 and ribs 15 may be omitted above the padelectrode PD. Note that, if the fourth insulating film 14 and ribs 15are disposed above the pad electrode PD, the fourth insulating film 14and ribs 15 are formed of an ultraviolet laser resistive material whichwill be described later.

A contact hole CHa is formed passing through the first insulatingsubstrate 10 and the insulating film IL to reach the pad electrode PD.The contact hole CHa includes a first contact hole CHa1 formed in thesecond area AR2 in the first insulating substrate 10 and a secondcontact hole CHa2 formed in the insulating film IL, which are continuedtogether. The pad electrode PD is formed above the first contact holeCHa1 and the second contact hole CHa2. The pad electrode PD and thecontact hole CHa are positioned immediately below the sealant SL. Thepad electrode PD and the contact hole CHa overlaps the second area AR2in the first insulating substrate 10 in the third direction Z. Notethat, in the present embodiment, the first contact hole CHa1 correspondsto a first through hole. Furthermore, the second contact hole CHa2corresponds to a second through hole.

A signal line 6 is, in the example depicted, formed on the insulatingfilm IL and is formed in the same layer where the second electrode P2 ofpad electrode PD is disposed. The signal line 6 is electricallyconnected to the pad electrode PD. The signal line 6 and the padelectrode PD may be formed separately or integrally. In the exampledepicted, the signal line 6 is formed integrally with the secondelectrode P2 of pad electrode PD. The signal line 6 corresponds to apower source line, and various control lines. The fourth insulating film14 covers the signal line 6, pad electrode PD, and insulating film IL.

Note that, the signal line 6 and the pad electrode PD may be disposed indifferent layers. Furthermore, the signal line 6 and the pad electrodePD may be formed in different layers such that the signal line 6 and thepad electrode PD are electrically connected through a contact holeformed in an interlayer insulating film therebetween.

The line substrate 1 is disposed below the first insulating substrate10. The line substrate 1 includes a core substrate 200, a connectionline 100 disposed on the surface of the core substrate 200 to be opposedto the display panel PNL, and driver 2 disposed on the surface oppositeto the surface of the core substrate 200 to be opposed to the displaypanel PNL. The core substrate 200 is disposed below the first area AR2and second area AR2 of the first insulating substrate 10.

The connection line 100 includes a projection T. The projection Tprojects toward the first substrate SUB1. The projection T is formedsuch that at least a part thereof is disposed inside the contact holeCHa. The projection T is formed on, for example, the connection line 100through plating or the like.

The driver 2 is electrically connected to the connection line 100through a through hole 110 formed in the care substrate 200. The driver2 functions as, for example, a signal supplier which supplies a signalto the display panel PNL for its drive. Note that the position of thedriver 2 is not limited to the above, and it may be disposed on thesurface of the core substrate 200 which is opposed to the display panelPNL.

The display panel PNL and the line substrate 1 are electricallyconnected and adhered together with an anisotropy conductive film 3which is a conductive material. Specifically, the anisotropy conductivefilm 3 includes conductive particles (conductive materials CP which willbe described later) dispersed in an adhesive agent. When the anisotropyconductive film 3 is interposed between the line substrate 1 and thedisplay panel PNL, they are pressed vertically in the third direction Zand heated to achieve electrical and physical connection therebetween.The anisotropy conductive film 3 is, between the display panel PNL andthe line substrate 1, filled inside the contact hole CHa from the lowersurface of the first insulating substrate 10 to contact and electricallyconnect with the first electrode P1 of the pad electrode PD.Furthermore, the anisotropy conductive film 3 contacts and electricallyconnects with the projection T of the connection line 100. Thereby, theconnection line 100 is electrically connected to the pad electrode PDand the signal line 6 through the anisotropy conductive film 3.

FIG. 4 is a cross-sectional view showing a part of the display deviceDSP of FIG. 3 in an enlarged manner, in which the line substrate 1,anisotropy conductive film 3, first insulating substrate 10, insulatingfilm IL, pad electrode PD, and the like are depicted.

As shown in FIG. 4, a conductive particle CP1 in the anisotropy film 3is interposed between the pad electrode PD and the projection T of theconnection line 100 in the contact hole CHa. When the line substrate 1is pressed against the display panel PNL, the conductive particle CP1 iscrushed between the projection T and the pad electrode PD to establishelectrical connection therebetween. Furthermore, in the exampledepicted, conductive particles CP2 in the anisotropy conductive film 3in the second area AR2 are interposed between the first insulatingsubstrate 10 and the connection line 100 outside the contact hole CHa.In this state, the conductive particles CP2 may be lodged in between thefirst insulating substrate 10 and the connection line 100. In thepresent embodiment, a state where the conductive particles CP2 arelodged means that the conductive particles CP2 are not pressed anyfurther by the pressure applied thereto when the line substrate 1 andthe display panel PNL are adhered together by pressing. The conductiveparticles CP1 and CP2 may be, for example, entirely formed of a metal ormay be formed, of a resin material coated with a metal material such asnickel or gold.

Note that, between the line substrate 1 and the display panel PNL, twoor more conductive particles CP are not made conductive while beingstacked in the third direction Z. Furthermore, for example, in both thefirst direction X and second direction Y, an adhesive agent (insulativematerial) which is a material for the anisotropy conductive film 3 isfilled between adjacent conductive particles CP, and thus, theconductive particles CP are rarely made conductive in both the firstdirection X and second direction Y.

Note that the surface of the connection line 100 which contacts theanisotropy conductive film 3 may have the projection T as shown or maybe flat without any projection. With the projections T formed as above,a greater number of conductive particles CP1 between the connection line100 and the pad electrode PD can be crushed by the projections T.Thereby, the electric connection between the connection line 100 and thepad electrode PD can be established more firmly with a smaller pressureforce. Thus, as compared to a case where there is no projection T, theproductivity and reliability of both the product and its production canbe improved.

FIG. 5 is a plan view of the first substrate SUB1 of the aboveembodiment, in which positions of the first area AR1 and the second areaAR2 or the like are depicted. In FIG. 5, the area where the sealant SLis formed is hatched up to right and is arranged to surround the displayarea DA.

The first insulating substrate 10 as in FIG. 3 is disposed over theentirety of the first substrate SUB1. The first area AR1 is, in a planview, an area where the protection member PP is disposed to overlap thefirst insulating substrate 10. The second area AR2 is, in a plan view,an area where the protection member PP does not overlap the firstinsulating substrate 10. Furthermore, as aforementioned, the thicknessW2 of the second area AR2 is less than the thickness W1 of the firstarea AR1.

In FIG. 5, the first area AR1 is hatched up to left. The protectionmember PP is disposed to overlap the entirety of the first area AR1. Thesecond area AR2 is adjacent to the first area AR1 and extends in thefirst direction X in the non-display area MDA in one end SUB1 e side ofthe first substrate SUB1. A plurality of pad electrodes PD and contactholes CHa overlap the second area AR2 in a plan view and are arrangedalong the first direction X. That is, the pad electrodes PD and thecontact holes CHa are disposed to overlap the thinner area of the firstinsulating substrate 10. Furthermore, the contact holes CHa are formedin a position overlapping the sealant SL in a plan view.

Now, a manufacturing method of the display device of the presentembodiment will be explained with reference to FIGS. 6 to 10. In FIGS. 6to 10, the structure above the pad electrode PD is equal to that of thepad electrode PD of the display panel PNL of FIG. 3, and thus, thedepiction thereof is omitted.

FIG. 6 is a cross-sectional view of a process in which a supportsubstrate 5 is peeled off from the first insulating substrate 10. Thatis, on the support substrate 5, members of the first substrate SUB1including the first insulating substrate 10, insulating film 11, padelectrode PD, signal line 6 and the like are formed one after another,and the second substrate SUB2 is adhered thereto.

Then, laser LL1 is irradiated from the rear surface side of the supportsubstrate 5 to peel the support substrate 5 from the first insulatingsubstrate 10. Here, in the present embodiment, the support substrate 5is formed of glass and the first insulating substrate 10 is formed ofpolyimide. The laser LL1 irradiated from the rear surface side of thesupport substrate 5 reaches the surface 10A of the first insulatingsubstrate 10. The first insulating substrate 10 absorbs and resolves thelaser LL1 at the interface between the support substrate 5 and the firstinsulating substrate 10. Thereby, a space is created at the interfacebetween the support substrate 5 and the first insulating substrate 10,and the support substrate 5 is peeled off from the first insulatingsubstrate 10.

FIG. 7 is a cross-sectional view showing a process in which theprotection member PP is adhered to the first insulating substrate 10.

The protection member PP is adhered to the first insulating substrate 10by an adhesive sheet (not shown). Specifically, while the adhesive sheetis disposed between the first insulating substrate 10 and the protectionmember PP, alignment of the protection member PP is performed, and aheat treatment is performed to make the adhesive sheet adhesive toadhere the protection member PP to the bottom of the first insulatingsubstrate 10. Thereby, a misalignment of the protection member PP can besuppressed.

Note that, before adhering the protection member PP to the firstinsulating substrate 10, a metal layer may be formed on the surface B ofthe protection member PP. The metal layer is formed by, for example,depositing a metal material on the surface B of the protection memberPP.

FIG. 8 is a cross-sectional view showing a process in which a firstcontact hole CHa1 is formed in the first insulating substrate 10.

After the adhesion of the protection member PP, ablation by excimerlaser is performed. That is, the first contact hole CHa1 is formed inthe first insulating substrate 10 by ablation using ultraviolet ofwavelength less than 350 nm. That is, from the lower side of the firstsubstrate SUB1, laser LL2 is irradiated to the area overlapping the padelectrode PD to form the first contact hole CHa1 in the second area AR2of the first insulating substrate 10 reaching the insulating film IL. Atthat time, in the area where the laser LL2 is irradiated, the firstinsulating substrate 10 absorbs the laser LL2 and resolves to form thefirst contact hole CHa1. The first contact hole CHa1 is formed in anarea RE overlapping the pad electrode PD in the third direction Z. Thus,the portion of the laser LL2 passing the insulating film IL through thefirst contact hole CHa1 is blocked by the pad electrode PD.

In the present embodiment, an excimer laser device is used as a sourceof the laser LL2. The excimer laser device will be, for example, a KrFlaser device having an emission wavelength of 248 nm, ArF laser devicehaving an emission wavelength of 193 nm, XeF laser device having anemission wavelength of 351 nm, or XeCl laser device having an emissionwavelength of 308 nm. In the present embodiment, laser of wavelength of258 nm or less should be used and the device is KrF laser device, forexample.

Note that the formation of the first contact hole CHa1 shown in FIG. 8may be performed before the adhesion of the protection member PP shownin FIG. 7.

FIG. 9 is a cross-sectional view showing a process in which the firstinsulating substrate 10 is thinned in the second area AR2 and a secondcontact hole CHa2 is formed in the insulating film IL.

After the first contact hole Cha1 is formed in the first insulatingsubstrate 10, a second contact hole CHa2 is formed in the insulatingfilm IL. The insulating film IL is trimmed in the first contact holeCHa1 through an ashing process to form the second contact hole CHa2. Thesecond contact hole CHa2 is formed in a position overlapping the firstcontact hole CHa1. The second contact hole CHa2 continues the firstcontact hole CHa1, and is formed between the pad electrode PD and thefirst contact hole CHa1. A gas used in the ashing process is, forexample, sulfur hexafluoride (SF6).

In the same process where the second contact hole CHa2 is formed, thefirst insulating substrate 10 is thinned in the second area AR2.Specifically, the first insulating substrate 10 exposed from theprotection member PP in the second area AR2 is trimmed by the ashingprocess to form the second contact hole CHa2. The first insulatingsubstrate 10 in the first area AR1 is not trimmed since it is coveredwith the protection member PP. Thus, the thickness W1 of the first areaAR1 is maintained as is before the ashing process, and the second areaAR2 becomes thinner than the first area AR1. At that time, theprotection member PP functions as a mask to prevent fragments from thefirst area AR1 in the ashing process. Furthermore, if a metal layer isformed on the surface B of the protection member B, the metal layer hasa resistance to the gas used in the ashing process, and thus, fragmentsfrom the protection member PP and deterioration in the propertiesrequired for the protection member PP (such as heat resistivity, gasinsulation, anti-humidity, and strength) can be suppressed.

Here, the insulating film IL and the first insulating substrate 10 reactto the gas used in the ashing process in different speeds. Thus, inconsideration of the reaction speed of each of the insulating film ILand the first insulating substrate 10 in the ashing process, thethickness thereof before the ashing process is determined. Thus, in thesecond area AR2, the first insulating substrate 10 can be trimmed to adesired thickness W2 while the insulating film IL is trimmed and piercedto reach the pad electrode PD.

As can be understood from the above, the process of forming the secondcontact hole CHa2 of the insulating film IL and the process of thinningthe first insulating substrate 10 can be performed concurrently in thepresent embodiment. Consequently, the first insulating substrate 10 cantoe thinned without an additional process. Furthermore, the productioncost can be suppressed.

As can be understood from the above, the ashing process of the firstinsulating substrate 10 is performed using the protection member PP as amask, and thus, a boundary surface 10 b between the first area AR1 andthe second area AP2 is positioned directly above the end surface PPe ofthe protection member PP.

FIG. 10 is a cross-sectional view showing a process in which the linesubstrate 1 is pressed to the display panel PNL.

As shown in FIG. 10, after the formation of the contact hole CHa in thefirst substrate SUB1, the line substrate 1 is pressed to the displaypanel PNL using the anisotropy conductive film 3. Specifically, theanisotropy conductive film 3 is disposed between the line substrate 1and the display panel PNL to be opposed to the contact hole CHa, and aforce is applied from the lower side of the line substrate 1 and theupper side of the display panel PNL as shown by arrows in FIG. 10 andheat is applied thereto. Thereby, the anisotropy conductive film 3 meltsand permeates into the contact hole CHa, and conductive particlesincluded in the anisotropy conductive film 3 contact the pad electrodePD to achieve electrical and physical connection between the linesubstrate 1 and the display panel PNL.

Through the above processes, the line substrate 1 is pressed to thedisplay panel PNL.

FIG. 11 is a cross-sectional view showing another example of forming afirst contact hole CHa1 in the first insulating substrate 10 of FIG. 8.In this example, the first contact hole CHa1 is formed to be shiftedfrom the area RE overlapping the pad electrode PD, and in this respect,this example differs from the example of FIG. 8. The first contact holeCHa1 is formed in a position overlapping the sealant SL.

As in the example of FIG. 8, in the area where the laser LL2 isirradiated, the first insulating substrate 10 absorbs the laser LL2 andresolves, and the first contact hole CHa1 is formed. In the formation ofthe first, contact hole CHa1, the laser LL2 irradiated in the area REoverlapping the pad electrode PD passes the insulating film IL throughthe first contact hole CHa1 and is blocked by the pad electrode PD, andthe laser LL2 irradiated may miss the area RE overlapping the padelectrode to reach the sealant SL passing the insulating film IL, fourthinsulating film 14, and rib 15.

The first insulating substrate 10 and sealant SL react the laser LL2 ifthe absorption wavelength to ultraviolet of the first insulatingsubstrate 10 and the sealant SL and the emission wavelength ofultraviolet of the laser LL2 match. In the present embodiment, thesealant SL has light absorbing ratio to ultraviolet wavelength less than350 nm which is lower than that of the first insulating substrate 10.Here, since the laser LL2 is 258 nm or less, the laser LL2 reacts withthe first insulating substrate 10 and barely reacts with the sealant SL.

However, depending on the material used therein, the sealant SL reactswith the ultraviolet light in the laser LL2 and the sealant SL mayresolve and sublimate. In such a case, the signal line 6 and the padelectrode PD may be damaged.

In the present embodiment, the sealant SL is formed of a material havinga lower light absorbing ratio to ultraviolet wavelength less than 350 nmthan that of the first insulating substrate 10, that is, a materialhaving an acrylate skeleton such as an acryl resin or an epoxy acrylateresin. Thus, if the laser LL2 misses the area RE overlapping the padelectrode PD and is irradiated on the first insulating substrate 10during the formation of the first contact hole CHa1, the laser LL2 afterpassing through the first insulating substrate 10 does not substantiallyreact with the sealant SL. Therefore, a line cut in the signal line 6and damage of the pad electrode PD caused by misalignment of the firstcontact, hole CHa1 can be suppressed and decrease of productivity can beprevented.

Furthermore, in the present embodiment, the first insulating substrate10 is thinner in the second area AR2 than is in the first area AR1.Therefore, as in FIG. 4, even if the conductive particles CP2 areinterposed and pressed between the connection line 100 and the firstinsulating substrate 10, a gap between the pad electrode PD and theprojection T of the connection line 100 in a position opposed to thecontact hole CHa can be decreased to sufficiently press the conductiveparticle CP1. That is, the conductive particle CP1 between theconnection line 100 and the pad electrode PD can be pressed and crushedbefore the conductive particles CP2 are lodged between the connectionline 100 and the first insulating substrate 10. Thus, the connectionbetween the connection line 100 and the pad electrode PD can beestablished more efficiently.

Furthermore, in the present embodiment, the display device DSP includesthe line substrate 1 disposed below the display panel PNL (in the rearsurface side which is opposite to the display surface) wherein the linesubstrate 1 and the display panel PNL are electrically connected throughthe conductive material (anisotropy conductive film 3 in the aboveexample) in the contact hole CHa. Furthermore, the driver 2 is disposedbelow the display panel PNL. Since the area of the first substrate SUB1is not required to be enlarged to mount the driver 2 or the linesubstrate 1 thereon, the first substrate SUB1 and the second substrateSUB2 cars be formed substantially even. Furthermore, in the area wherethe first substrate SUB1 and the second substrate SUB2 are opposed toeach other, the display area DA can be increased. That is, in thedisplay surface of the display device DSP of the present embodiment, thearea of the display area DA used for display can be increased, and athinner bezel structure can be achieved.

Furthermore, since there is no need of a long flexible printed circuitused for the electrical connection between the part of the firstsubstrate SUB1 which is opposed to the second substrate SUB2 and theline substrate 1, or a space to accommodate a bent flexible printedcircuit, the display device DSP can be miniaturized. Furthermore, anelectronic device including the display device DSP can be miniaturized,too.

Furthermore, since a possible breakdown of the lines when the flexibleprinted circuit is bent can be avoided, the display device DSP can bemore reliable.

FIG. 12 is a schematic plan view showing positional relationshipsbetween the pad electrode PD and the first contact hole CHa1.

In the example of FIG. 12(a), the first contact hole CHa1 is formed inthe area of the pad electrode PD. This is a structure corresponding tothe example of the first contact hole CHa1 and the pad electrode PDshown in FIG. 8. The laser to form the first contact hole CHa1 isblocked by the pad electrode PD and does not reach the sealant SL. Inthe example of FIG. 12(b), the first contact hole CHa1 is shifted in thesecond direction Y as compared to the example of FIG. 12(a), and thefirst contact hole CHa1 is formed partly out of a side edge PDX of thepad electrode PD, which is parallel to the first direction X. This is astructure corresponding to the example of the first contact hole CHa1and the pad electrode PD shown in FIG. 11.

In the example of FIG. 12(c), the first contact, hole CHa1 is shifted inthe first direction X as compared to the example of FIG. 12(a), and thefirst contact hole CHa1 is formed partly out of a side edge PDY of thepad electrode PD, which is parallel to the second direction Y. Even ifthere is a misalignment of the first contact hole CHa1, the sameadvantage explained above can be achieved.

In the example of FIG. 12(d), the first contact hole CHa1 is expanded inthe first direction X to be greater than the width of the pad electrodePD and is formed to be partly out of the side edges PDY1 and PDY2 of thepad electrode PD in the first direction X. For example, even if the padelectrode PD is reduced, in width in the first direction X for higherdefinition of the display device, and the size of the first contact holeCHa1 is made smaller than the size of the pad electrode PD, the sameadvantage explained above can be achieved.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

For example, the above insulating film IL includes the first insulatingfilm 11, second insulating film 12, and third insulating film 13;however, no limitation is intended, thereby. Various changes can beapplied thereto. For example, the insulating film IL may be a monolayerinsulating film, or may be a double-layered insulating film, or may bean insulating film including four or more layers.

Furthermore, in the above embodiment, the sealant SL is used as anorganic member which is directly above the pad electrode PD between thefirst substrate SUB1 and the second substrate SUB2; however, nolimitation is intended thereby. For example, a different organic membermay be interposed between the first substrate SUB1 and the sealant SL.In that case, the organic member is closer to the pad electrode PD thatis the sealant SL, and thus, the organic member is formed of a resinmaterial of acryl or epoxy acrylate as in the above embodiment while thesealant SL which is above the organic member may be formed of variousmaterials. Furthermore, the sealant SL surrounding the display area DAmay be omitted. In that case, the acrylate 41 shown in FIG. 3 or thelike may extend to the part directly above the pad electrode PD. At thattime, the acrylate 41 is formed of a resin material of acryl or epoxyacrylate as in the above embodiment.

Furthermore, the above organic member may be interposed between theacrylate 41 and the first substrate SUB1.

The above embodiment may be applied to a liquid crystal display deviceinstead of an organic electroluminescent display device. In that case,the display panel PNL is, for example, a liquid crystal display panelincluding a liquid crystal layer interposed between the first substrateSUB1 and the second substrate SUB2. A liquid crystal display panel asthe display panel PNL may be of reflective type which selectivelyreflects light incident from the second substrate SUB2 side of may be oftransmissive type which selectively transmits light incident from thesecond substrate SUB2 side. Note that, in a plan view, if the displayarea DA and the line substrate 1 overlap each other, the reflective,type is suitable; however, the reflective type may be adopted when abacklight unit can foe dispose between the first substrate SUB1 and theline substrate 1. Note that the main structure of the present embodimentis substantially the same even if the display device DSP is a liquidcrystal display device.

What is claimed is:
 1. A display device comprising: a first substrateincluding an insulating substrate with a first through hole, a padelectrode positioned above the insulating substrate, and a signal lineelectrically connected to the pad electrode; a second substrate opposedto the first substrate; a sealant which adheres the first substrate andthe second substrate; a line substrate including a connection line anddisposed below the insulating substrate; and a conductive material whichelectrically connects the pad electrode and the connection line, whereinthe pad electrode and the first through hole overlap the sealant, afirst part of the first through hole does not overlap the pad electrodeand overlaps the sealant, and a second part of the first through holeoverlaps both of the pad electrode and the sealant, and the sealant isless absorptive than is the insulating substrate as to a wavelength lessthan 350 nm.
 2. The display device of claim 1, wherein the sealant isformed of a material having an acrylate skeleton.
 3. The display deviceof claim 1, further comprising an adhesive agent surrounded by thesealant.
 4. The display device of claim 3, wherein the adhesive agent isformed of a material which is different from that of the sealant.
 5. Thedisplay device of claim 1, further comprising an insulating film betweenthe insulating substrate and the pad electrode, and a second throughhole between the pad electrode and the first through hole, the secondthrough hole being connected to the first through hole.
 6. The displaydevice of claim 5, wherein the insulating film is an inorganicinsulating film.
 7. The display device of claim 6, wherein theinsulating film includes at least a first insulating film and a secondinsulating film, and the first insulating film and the second insulatingfilm are formed of different materials.
 8. The display device of claim1, wherein the insulating substrate is a resin substrate.
 9. The displaydevice of claim 1, wherein the pad electrode includes a first electrodecontacting the conductive material, and the first electrode is atransparent conductive layer.
 10. The display device of claim 9, whereinthe pad electrode includes a second electrode disposed on the firstelectrode, and the second electrode is formed of a metal material. 11.The display device of claim 1, further comprising a light emittingelement disposed between the first substrate and the second substrate.12. A display device comprising: a first substrate including aninsulating substrate with a first through hole, a pad electrodepositioned above the insulating substrate, and a signal lineelectrically connected to the pad electrode; a second substrate opposedto the first substrate; an organic member positioned between the firstsubstrate and the second substrate; a line substrate including aconnection line and disposed below the insulating substrate; and aconductive material which electrically connects the pad electrode andthe connection line, wherein the pad electrode and the first throughhole overlap the organic member, a first part of the first through holedoes not overlap the pad electrode and overlaps the organic member, anda second part of the first through hole overlaps both of the padelectrode and the organic member, and the organic member is lessabsorptive than is the insulating substrate as to a wavelength less than350 nm.
 13. The display device of claim 12, wherein the organic memberis formed of a material having an acrylate skeleton.
 14. The displaydevice of claim 12, wherein the insulating substrate is a resinsubstrate.
 15. The display device of claim 12, further comprising aninsulating film between the insulating substrate and the pad electrode,and a second through hole between the pad electrode and the firstthrough hole, the second through hole being connected to the firstthrough hole.
 16. The display device of claim 15, wherein the insulatingfilm is an inorganic insulating film.
 17. The display device of claim16, wherein the insulating film includes at least a first insulatingfilm and a second insulating film, wherein the first insulating film andthe second insulating film are formed of different materials.
 18. Thedisplay device of claim 12, wherein the pad electrode includes a firstelectrode contacting the conductive material, and the first electrode isa transparent conductive layer.
 19. The display device of claim 18,wherein the pad electrode includes a second electrode disposed on thefirst electrode, and the second electrode is formed of a metal material.